[TR] 61 TR3A SU H6 Carb Issues
trguy75 at gmail.com
Tue Oct 16 07:07:17 MDT 2018
Great discussion thread on your web link. You are right it could be 100 different things. It ran much better before the carb rebuild so I am thinking it is in the carbs. I may go back and check all steps again and eliminate steps one by one. Such fun normally, except I am eager to get back on the road as the weather turned nicer in FL.
From: Paul Tegler <ptegler at verizon.net>
Sent: Monday, October 15, 2018 11:23 PM
To: Jim Henningsen <trguy75 at gmail.com>; triumphs at autox.team.net
Subject: Re: [TR] 61 TR3A SU H6 Carb Issues
ok....what do you mean by 'carbs aren't running smoothly' ?
Engine is not smooth?.. sputtering? not running smooth while cruising?
An old adage.... (well two actually)
"..most carb problems are electrical..." and "..most ignition problems are the carbs"
Seriously though.... what method didyou use to balance the air flow at idle? One of those little flow meters?
NOPE NADA STOP right there. Think about it...you're sealing off the air to get the bubble to rise so of course the idle changes....so the balance tube in the manifold sucks from the other carb, bypassing the fuel pull.
I was finally convinced by an old mechanic and have learned from tuning more SU and ZS carbs than I care to mention.... use a 1/4" fuel line as a stethoscope ...one end in your ear..the other just up against the edge (not in) the carb throat. blocks minimal air... and believe me you can hear as little 1-2 cfm readily, but you can also hear the gurgle of the fuel flow! Years ago I actually gave away my flow gauges.
Eons ago..I got so fed up once I bought brand new NOS SU carbs to replace mine after three rebuilds of the orig units. BUT...STILL had the same issue...smooth speed cruising and it ran like crap. Pull the choke out and it ran fine, but had to push it in at closed or low speed throttle. Spent a year+ and hundreds of messages on various LBC lists....still to no avail. Than one day at a car show.... I saw a guy with an identical setup.... open big round K&Ns and a end plate but had his air filters nearly 3/4 closed off with duct tape. In the end, the problem was incorrect vacuum effects ...not enough air velocity when the piston was mid/down as there was no restriction from the air filters.
On 10/15/2018 7:40 PM, Jim Henningsen wrote:
Ok, I thought I had this rebuild all nailed down. Finally got around to
getting carbs balanced and set for correct mixture. After new kits, testing
piston drop timing per John Twist you tube clip (great clip), and spending
two hours fine tuning air flow and mixture. The carbs aren't running
smoothly. There is something not right and I am throwing in the towel.
Don't have a reliable mechanic that I trust for this in Ocala. Any
recommendations on a rebuilder to send these two to have them checked
Jeff Payla at Paltech - cant seem to get a response from him.
Buy new (ouch)
Thanks in advance
61 TR3A eager to enjoy driving it in fall in Florida
62 TR4 eager to have restoration finished
75 TR6 eager to have new race motor put in
82 Jeep ld reliable - get in and go
2002 Triumph Trophy 1200 eager to just get out and be used.
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